Apparently Connected Advanced USB Charger Survey

[Gallymimus]

Our friends have a Kickstarter for a new high tech USB mobile device charger launching soon (next few months).  We need some feedback from YOU on the device.  There is gift card giveaway (might only be useful in the US though) if you participate as a small thanks for your time on the survey!  Thanks for the help.

Go to Survey HERE---->         http://svy.mk/1gyMyc9

[minibutmany]

It is unclear, does this unit have a battery in it? Or does it connect to AC power to charge the devices?

[Gallymimus]

This would be a line powered device (to be exact using a power brick located elsewhere).  It's a high power charger so there wasn't a better way to keep it sleek without bulking up.

[nathancrum]

It's meant to look anodized red, not pink - not that there's anything wrong with pink.     It will also be available in black, blue and clear to start with - push goals could open up more color choices.

Regarding advantages compared to the average multi-port charger available:

• Every port has a full 3.0A of charging capacity (simultaneously - 60W total)
• Every port has a dedicated microprocessor trimmed LDO regulator
• The input power is regulated to just above the LDO dropout using a multi-phase buck converter for low noise and higher LDO efficiency
• Together this results in very good voltage accuracy and extremely low output noise (nearly zero transient voltages even without a load)
• Every port is monitored for current and voltage - providing live feedback, charging status and current limiting
• Every port has a dedicated charge protocol controller providing true universal high-speed charging for all devices (Apple, Samsung, etc.)
• It's housed in a billet machined enclosure - some people may like that, some may not, but it's durable and I think sexy looking.

That's most of the highlights anyway.  It's not a cure for cancer - it's just meant to be a very high quality charger.

[Zbig]

I stopped reading after "The most advanced USB charger ever made" and "most sophisticated high-power, 4 port USB charger on the planet". Slogans like this make me wanna cry. Or puke. No, wait, make that both.

[Gallymimus]

I stopped reading after "The most advanced USB charger ever made" and "most sophisticated high-power, 4 port USB charger on the planet". Slogans like this make me wanna cry. Or puke. No, wait, make that both.

Fair comment,  What would you say to earn credibility if you believed you had something better than what was on the market?  What kind of phrasing would appeal to you or convince you?

[Rerouter]

That comes down a bit to how you have tested it, if you actually designed it with parts quality in mind saying things like "Built with quality and robustness in mind to make the most flexible high current charger on the market" or similar while still marketing, it doesn't exactly shun the engineer type guys away by sheer buzzwords

(claiming something is the most advanced implementation of what is generally a simple device is what turns them away)

[nathancrum]

I stopped reading after "The most advanced USB charger ever made" and "most sophisticated high-power, 4 port USB charger on the planet". Slogans like this make me wanna cry. Or puke. No, wait, make that both.

I understand what you mean.  We're definitely not marketing guru's and could probably benefit from tempering the wording to sound more credible, but we don't think those are outrageous claims either.  There are only a couple chargers anywhere on the market with similar quality and sophistication (for use with very high end DAC's), but they're not multi-port and they're not really intended to charge anything - they're for directly powering sensitive audio equipment. 

We've taken a traditionally simple and cheap product and engineered the hell out of it and that's a value proposition we're still trying to figure out how to craft for a wide audience - both tech/engineers and average consumers.  You're probably right though - buzz words are probably more universally harmful than helpful.  I don't know of a simple way to sum up everything we've designed into this charger without a few of them though - will have to hit the thesaurus and get creative.

Thanks

[Richard Crowley]

So all of those claims may be true. But what difference does it actually make to have "low noise and higher LDO efficiency" or "very good voltage accuracy and extremely low output noise"?
If I am only charging a device (or even POWERING a device, for that matter) why should any of this actually matter to the customer? Why would it be to my advantage to have a "premium" USB charger?  Why would I buy a gold (or even gold-plated) screwdriver? 

A charger is a low-end utility item that does not require "precision", but only "competence". You would have to convince us why "precision" is of any practical value to the end-user?

I recently bought one of these gadgets at my local cable shop for US$38 and it doesn't need a wall-wart.  Brilliant:

[Gallymimus]

That comes down a bit to how you have tested it, if you actually designed it with parts quality in mind saying things like "Built with quality and robustness in mind to make the most flexible high current charger on the market" or similar while still marketing, it doesn't exactly shun the engineer type guys away by sheer buzzwords

(claiming something is the most advanced implementation of what is generally a simple device is what turns them away)

Thanks for the comment.  You are certainly right.  We'll look at that approach when we put together the final marketing package.  It's always hard to pick the marketing tone depending on who the audience is.  With a new product we don't know who the audience will be.  I suspect it won't be so many of the engineers but more of the sky mall and sharper image crowd.

[Gallymimus]

So all of those claims may be true. But what difference does it actually make to have "low noise and higher LDO efficiency" or "very good voltage accuracy and extremely low output noise"?
If I am only charging a device (or even POWERING a device, for that matter) why should any of this actually matter to the customer? Why would it be to my advantage to have a "premium" USB charger?  Why would I buy a gold (or even gold-plated) screwdriver? 

A charger is a low-end utility item that does not require "precision", but only "competence". You would have to convince us why "precision" is of any practical value to the end-user?

I recently bought one of these gadgets at my local cable shop for US$38 and it doesn't need a wall-wart.  Brilliant:

Again good comment.  So we've thought about this and you are right.  How do you convey value.  As an engineer I'm with you.  A very weak argument is products like Monster cable and motherboards which claim solid capacitors and multiphase converters are certainly questionable from an engineering standpoint yet they do quite well on the market (I think!). 

We are still doing some testing but one of the areas where the precision and low noise has benefit is in the audio space.  You may have seen that there is a community of audiophiles who buy USB DACs and want clean power for those devices.  We're looking into whether the phones have lower audible noise with the precision voltage regulation.

Another thing that isn't often included in the chargers like the one you highlighted is they often can supply 8A max, but really can't negotiate the 2 or 2.5A charge current to the higher end tablets or other apple devices.  If you happen to have tried measuring on yours it would be a great data point.  Typically they really supply about 1 to 1.5A because the D+ and D- pins are simply shorted together in the charger (which corresponds to the standard USB dedicated charging port spec).

it's in the same vein of buying a Lexus vs a Toyota.  There are some niceties, features, and levels of quality that are far beyond the basic options.  Is this worth it?  Well some consumers say heck yeah and many don't.

Really appreciate the discussion.  We of course want to put the best foot forward on the product and have the greatest appeal for it even though it will never capture EVERYONE's interest.

[tom66]

I really doubt the average phone is designed for low-noise audio. You've got a 3W radio drawing power from the same source now and then and within 10cm of the audio electronics. It doesn't matter how clean your input power supply is if that happens to transmit.  Not to mention the typically cheap DAC that is used because cost > some audiophile nonsense.

Presumingly you're running off a 12V(?) plugpack with whoever knows what type of crappy flyback it in spitting emi everywhere, make sure to test that.

Make sure the desired PSRR LDO @ frequency of your switcher exceeds that of a better designed high frequency switcher...

[mariush]

Every port has a full 3.0A of charging capacity (simultaneously - 60W total)

which would be pointless if you don't controller the data lines to simulate various standards (there are ICs that detect the device and "talk" to device and enable high current)

Every port has a dedicated microprocessor trimmed LDO regulator
The input power is regulated to just above the LDO dropout using a multi-phase buck converter for low noise and higher LDO efficiency
Together this results in very good voltage accuracy and extremely low output noise (nearly zero transient voltages even without a load)

Which is pointless... by definition the usb voltage is 5v +/- 5% or something like that, so devices MUST be tolerant of variations in voltage, must consider the cable length causing some voltage drop etc etc...

• Every port has a dedicated charge protocol controller providing true universal high-speed charging for all devices (Apple, Samsung, etc.)

now you mention it...

[zapta]

I recently bought one of these gadgets at my local cable shop for US$38 and it doesn't need a wall-wart.  Brilliant:

Looks nice, what model?

As for the OP, you started the price choices at $50. You should have lower prices, don't assume other people value it as you are.

Edit: I am using this $5 device to debug charging speed.  http://www.apparentlyconnected.com/wp-content/uploads/2013/12/Idea-03.09.jpg  You plug charger and cables until you get a good reading (e.g. >1A for a phone).

[nathancrum]

We really appreciate the feedback, but I don't want to get too side-tracked on the quality issue.  The fact is - we need to collect a lot more data and even with a mountain of it - making definitive statements about what someone *needs* with regard to voltage stability, accuracy and precision is going to be almost impossible.  That said - we do think noise matters and there are tangible differences.  Attached are samples of a 60 Hz audio tone from a smartphone on battery power vs. on a poor quality charger (I haven't had the chance to test on our circuitry yet).  Can your device operate with low quality power?  Certainly - many millions do every day.  Do you want to submit your $700 smart phone or tablet to poor quality power every day if there's an alternative?  That's up to you.

There are a few significant advantages to our charger that are not subjective though too:

• 3.0A on every port is unique.  Most multi-port chargers provide only one high power port and/or 2.1A is the most common maximum currently.  It's highly probable that max will get increased again as manufacturers chase ever faster charging batteries and more power hungry devices.
• Automatic protocol negotiation for high power charging is extremely rare.  Most chargers support only one device family (there are at least 3 major families: Apple, Samsung and pretty much everything else).  If your device is incompatible - it will charge at reduced rate (500mA).
• Feedback.  Most chargers provide none.  Ours provides color-coded LED status indicators on each port.  We have not yet explored all the ways this can be used, but we expect to be able to show when a device is nearly finished charging, when it's done, just started, etc.  The original post was asking if there was any perceived advantage to adding an OLED screen for more feedback (power drawn, time charged, voltage, etc.)
• Current and voltage monitoring.  Besides being able to trim voltage for accuracy, our charger also has the capability to 'watchdog' the output and cut it if something goes wrong with the host device and it starts drawing too much current.

Again - we appreciate the feedback - please keep it coming.  Let's try not to get too bogged down in whether you view quality as worthwhile.  Some people buy cheap components and expect to have them fail or be inferior.  Others want quality and craftsmanship and of course there's also every shade in between.  We're trying to appeal towards the later end of the spectrum - admittedly - without urgent, demonstrated need.  I know for ourselves at least - we wanted to push back the race-to-the-bottom and build a better product - one that might actually last awhile, one that performs well and one that looks good on our desk.  Hopefully we're not alone in those desires.

[zapta]

Automatic protocol negotiation for high power charging is extremely rare.  Most chargers support only one device family (there are at least 3 major families: Apple, Samsung and pretty much everything else).  If your device is incompatible - it will charge at reduced rate (500mA).

That's a very good feature and can be a strong selling point. Does it mean that regardless of the USB cable configuration and the device type your charger will be detected as AC rather than USB?

As for the audio of the ripple, that's reminds me late nigh informercials. I wouldn't take it seriously.

[Gallymimus]

I really doubt the average phone is designed for low-noise audio. You've got a 3W radio drawing power from the same source now and then and within 10cm of the audio electronics. It doesn't matter how clean your input power supply is if that happens to transmit.  Not to mention the typically cheap DAC that is used because cost > some audiophile nonsense.

Presumingly you're running off a 12V(?) plugpack with whoever knows what type of crappy flyback it in spitting emi everywhere, make sure to test that.

Make sure the desired PSRR LDO @ frequency of your switcher exceeds that of a better designed high frequency switcher...

Yep,  you are right.  We've yet to prove that the switching noise from a standard charger (with a few hundred mv of ripple) is audible or not.  We're using a small multiphase converter, LC filters, and the LDO.  So far it's proven to reduce the electrical noise substantially.  The switching noise from the brick (24V actually) doesn't make it through in any significant way.

But yeah, the phones aren't the best audio devices, but if it makes a difference it would be a bullet point. 

[Gallymimus]

Every port has a full 3.0A of charging capacity (simultaneously - 60W total)

which would be pointless if you don't controller the data lines to simulate various standards (there are ICs that detect the device and "talk" to device and enable high current)

Every port has a dedicated microprocessor trimmed LDO regulator
The input power is regulated to just above the LDO dropout using a multi-phase buck converter for low noise and higher LDO efficiency
Together this results in very good voltage accuracy and extremely low output noise (nearly zero transient voltages even without a load)

Which is pointless... by definition the usb voltage is 5v +/- 5% or something like that, so devices MUST be tolerant of variations in voltage, must consider the cable length causing some voltage drop etc etc...

• Every port has a dedicated charge protocol controller providing true universal high-speed charging for all devices (Apple, Samsung, etc.)

now you mention it...

Yep spot on.  Tolerance is actually 10% so it's even worse than you suggest.  This is a premium product and some people care some don't.  In fact one of our planned features is a boost mode which pushes the 5V to 5.5V to improve the charging performance by an additional 10%

[Gallymimus]

Automatic protocol negotiation for high power charging is extremely rare.  Most chargers support only one device family (there are at least 3 major families: Apple, Samsung and pretty much everything else).  If your device is incompatible - it will charge at reduced rate (500mA).

That's a very good feature and can be a strong selling point. Does it mean that regardless of the USB cable configuration and the device type your charger will be detected as AC rather than USB?

As for the audio of the ripple, that's reminds me late nigh informercials. I wouldn't take it seriously.

yes that's correct on the AC vs USB for charging.

I think what will make the audio point truly relevant to regular people is if we provide some audio samples that show a modest audible difference.  That would sell me on it if I were a potential customer.

[rfbroadband]

I assume you guys looked at the thermal design aspects of this when all ports provide the full load of 3A?

[Gallymimus]

I assume you guys looked at the thermal design aspects of this when all ports provide the full load of 3A?

Yes Sir.  One of the things we are doing is adjusting the muliphase converter to be just above the dropout voltage of the LDOs to minimize heat lose.  The multiphase should be about 92% so that's a few watts and the LDOs will each lose about a watt each.  Given the aluminum enclosure heat shouldn't be a problem, though it will get slightly warm to the touch.  Efficiency hopefully won't be a big issue since we aren't talking about "vampire power" and the regulators will be shut down when there isn't a current draw.

This has be a point of skepticism for us when looking at other chargers on the market that claim 8A for instance.  A few watts in a sealed plastic box builds up heat pretty quickly.

Thanks for the comment!

[tom66]

92% efficiency is that real world or datasheet best case?

92% is pretty typical for the mid-point of operation of a switcher, but remember they typically roll off on efficiency as you approach maximum load; 92% sounds more like a mid-loading best case efficiency point.

But if you assume 92% efficiency you need to get rid of 5W in your switcher (not impossible, but challenging) plus 1W per port. Your aluminium widget will dissipate 9W so it will run quite hot.  This heat  will decrease efficiency further (ON-resistance of MOSFET increases with temperature) so make sure to do a full load burn-in test on the final product.

[Gallymimus]

92% efficiency is that real world or datasheet best case?

92% is pretty typical for the mid-point of operation of a switcher, but remember they typically roll off on efficiency as you approach maximum load; 92% sounds more like a mid-loading best case efficiency point.

But if you assume 92% efficiency you need to get rid of 5W in your switcher (not impossible, but challenging) plus 1W per port. Your aluminium widget will dissipate 9W so it will run quite hot.  This heat  will decrease efficiency further (ON-resistance of MOSFET increases with temperature) so make sure to do a full load burn-in test on the final product. 

Great point!  I hope we won't have to use a thermal gap pad material to conduct heat to the aluminum billet but we have that as a fallback if needed.

The switchers we are using approach max efficiency as load increases (losses are primarily switching), also it's a multiphase so the switching/rdson losses are distributed across 4 switches (synchronous dual phase buck), and copper losses are distributed across 2 inductors.

92% was a mid to high load back of napkin calculation based on the other switchers we've done for customers.  It IS going to get a bit warm so we'll see how it ends up!

The datasheet doesn't actually quote efficiencies.  We've got some work to do on tradeoff between component sizes, switching frequency and end efficiency.  As you know there are a lot of competing variables in a switcher design.

You are right, a full burn in test on several prototypes running at a 50C ambient is mandatory to prove out a high quality robust design.  No cutting corners if you don't want to have failures.  I'm no genius and often miss things on the first prototypes.

Thanks for the suggestions, we don't want to miss anything that we don't have to.

[Gallymimus]

Arriving just in time to be made redundant by wireless charging. I haven't plugged my phone into anything for months.

Great point.  certainly wireless charging is a sexy competitor to a physical cable.

Except that wireless charging isn't suitable for many application.  For instance, if you want to charge fast wireless currently isn't suitable.  The current implementation of the Qi charging spec only supports 1A (5W) while were talking about 3 times faster than that.  If I'm in a hurry I don't want to wait 3x longer to get my tablet or phone charged.

I have a Qi charger at my home and use it for my tablet each night.  It's OK, but hardly awesome.  It definitely serves it's purpose and for slow lazy charge overnight I love it.

Which devices / wireless charger are you using?  I find it's a pain to align my tablet over the coil on the charger, maybe you don't have that problem with yours.  Do all of your devices support the wireless charging pad you are using?

USB charging is going to be around for a while, Especially since the new charger spec (USB Power Deliver Spec 1.0 http://www.usb.org/developers/powerdelivery/) will support 12 and 20V and up to 5A.  We will likely see monitors and notebook computers powered via the new USB specs.  Wireless won't be getting there for some time.

[peter.mitchell]

how well does it respond to abuse? (shorted output, shorts between gnd and data, shorts between v+ and data, 12v down the 5v line )